This investigation is centered on the study and characterization of spontaneous cataracts in Bobwhite quail. Light and electron microscopy are being utilized to evaluate morphologic alterations in cataractous lenses. The role of various types of light and different kinds of exposure are also being investigated as possible factors in the development of lens opacities. A comparison of the incidence of cataracts at chronologic intervals is being conducted in conjunction with the morphologic progression of cataracts as quail mature and grow old. Biochemical studies are also in progress to identify changes in free amino acid distribution and to determine the protein and non-protein sulfhydryl levels in normal and cataractous lenses. The overall goal of the project is to develop an avian model for comparative cataract research so that further studies may be conducted to identify mechanisms of cataract formation in man.